Becquerel’s experiment consisted of four steps. 1. Get a sample of a uranium salt.
2. Expose the salt to sunlight.
3. Expose photographic plates to the salt.
4. Develop the plates.

A change in which step led to Becquerel’s discovery of radioactivity?
1
2
3
4

Acamcorder has a power rating of 17 watts. if the output voltage from its battery is 7 volts, what current does it use?units:

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.